AU2009203202B2 - A vehicle having a ramp arrangement - Google Patents

Abstract

A trailer vehicle 22 for carrying a load vehicle is disclosed that includes a chassis and a main load support 26. It also includes a ramp arrangement 12 including two 5 ramp parts that together a traverse surface. One ramp part 32 is pivotal between a horizontally extending traveling position and a downwardly extending operative position. The other ramp part 34 is mounted on the one ramp part 32 and is displaceable relative thereto to vary the traverse surface as required. The main load support 26 and the ramp arrangement 12 are together interchangeable as a 10 unit between a laterally narrowed condition and a laterally expanded condition in which side edges of the load support 26 and the ramp arrangement 12 are spaced outwardly of the sides of the chassis. This enables load vehicles of greater than usual width to be carried on the load support 26 and also to be driven up and down the ramp arrangement 12. FIG 20 for publication clil (3

Description

A VEHICLE HAVING A RAMP ARRANGEMENT

FIELD OF THE DISCLOSURE

This disclosure relates to a vehicle having a ramp arrangement. This disclosure also extends to a trailer vehicle having a ramp arrangement.

This disclosure relates particularly but not exclusively to a ramp arrangement for a trailer, and a heavy trailer or semi-trailer including the ramp arrangement. It will therefore be convenient to hereinafter describe this disclosure with reference to this example application. At the same time however it should be realized that the disclosure is capable of broader application. For example this disclosure could equally be applied to a ramp arrangement for a vehicle having its own motive power such as a truck or the like. It does not need to be a trailer that is coupled to a prime mover.

DEFINITION

In the specification the term “comprising” shall be understood to have a broad meaning similar to the term “including” and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” and “comprises”.

BACKGROUND TO THE DISCLOSURE

Fleavy duty trailers for over the road hauling of heavy loads are a ubiquitous feature of modern industrialized economies. In particular trailers can be used for transporting equipment for moving across the ground such as trucks, cars, tractors, bobcats, forklift trucks, front end loaders, bull dozers and other ground moving equipment.

Such ground engaging load vehicles, are generally carried or supported on the deck of a heavy trailer when they are moved from one location to another. During operation it is necessary to load the vehicles on the deck of the trailer and also to unload the load vehicles from the deck of the trailer. This can conveniently be done by providing a driving ramp arrangement at the tail end or rear end of the deck of the trailer. The load vehicle can be driven up the ramp to load it on the deck of the trailer and can be driven down the ramp to unload it from the deck of the trailer.

In the prior art it has been known to provide two parallel track ramps, one towards each side of the vehicle, e.g. trailer, to form the driving ramp arrangement. One such example is shown in Fig 1 of the drawings. As shown the two parallel track ramps are operatively able to pivot between a downwardly inclined operative position extending rearwards away from the vehicle in which they form a ramp up which and down which a vehicle can be moved and a vertically upstanding inoperative (stowed) position or traveling position.

When the trailer is in use being towed on a road the ramps are in their inoperative or traveling position. When the trailer is stationary and it is desired to offload vehicles the track ramps are pivoted from the inoperative position down into their operative position. The ramp tracks form a ramp that extends from a deck of the trailer down onto the support surface on which the trailer is supported and load vehicles can be moved off the trailer deck and down onto the support surface and vice versa. A disadvantage of this driving ramp arrangement with the two track ramps is that the two track ramps project vertically upward when the trailer is driven along a road. This arrangement with the upstanding track ramps has a high drag coefficient and causes high level of drag resistance particularly when the trailer is traveling along the road at normal road traveling speeds. Yet further it requires a significant pivoting action of bulky track ramps to change the ramps from the upstanding inoperative position to the operative position. The moment applied to the track ramps when they are being lowered into the operative position is clearly substantial.

In the current world environment there is a drive to reduce energy consumption and particularly fuel consumption and it would therefore be advantageous to devise a more energy efficient way of providing a trailer with a ramp arrangement for loading vehicles onto the trailer and unloading vehicles from the trailer than the prior art method described above. It would also be advantageous if an elegant engineering solution could be devised that provided a ramp that was quick and easy to move between the operative and inoperative positions.

The reference to prior art in the background above is not and should not be taken as an acknowledgment or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia or in any other country.

SUMMARY OF THE DISCLOSURE

According to one aspect of the disclosure there is provided a trailer vehicle for carrying a load that includes: a chassis; a main load support having a load bearing surface mounted on the chassis, the main load support includes a central stationary load support section that is fixedly mounted on the chassis and two movable load support sections, one on each side of the central load support section that can be slidably displaced in translational fashion between a laterally narrowed condition and a laterally expanded condition; and a ramp arrangement for forming a ramp surface from the load bearing surface to a road surface, the ramp arrangement including a central stationary ramp section and two movable ramp sections, one on each side of the central ramp section, each movable ramp section is directly mounted in pivotal fashion on its associated movable load support section so that the load support section and ramp section move together between the laterally narrowed and laterally expanded conditions, and wherein each movable ramp section includes one pivoting ramp part and another extensible ramp part, said one pivoting ramp part being proximate to and pivotally mounted on its associated movable load support section and the other extensible ramp part being mounted on the one pivoting ramp part, the other extensible ramp part being slidably extendable in translational fashion relative to the one pivoting ramp part to increase the ramp surface and being slidably retractable to decrease the ramp surface.

The central stationary ramp section may be pivotally mounted on the central stationary load support section, and the stationary ramp section may include one pivoting ramp part and another extensible ramp part like the corresponding parts of the movable ramp sections.

The load support and the ramp arrangement may be positioned closely adjacent to each other in the laterally narrowed condition, and lateral side edges of the load support and the ramp arrangement may be spaced laterally out beyond outer side edges of the chassis of the trailer vehicle in the laterally expanded condition.

Each said pivoting ramp part may be pivotally mounted about a transverse pivot axis towards a rear end of the main load support, and may be pivotally displaceable about the pivot axis between an operative position in which the traverse surface inclines downwardly away from the load bearing surface, and a traveling position in which the traverse surface extends substantially horizontally outward away from the load bearing surface.

The trailer vehicle may include a drive means for driving each movable main load support section and its associated movable side ramp section between the laterally narrowed and laterally expanded conditions.

The drive means may include one hydraulic drive arrangement for driving one movable load support section together with its associated movable ramp section, from the laterally narrowed to the laterally expanded condition and back to the laterally narrowed condition. The drive means may include another hydraulic drive arrangement for similarly driving the other movable load support section together with its associated movable ramp section, from the laterally narrowed to the laterally expanded condition and back to the laterally narrowed condition.

Each hydraulic arrangement may include a cylinder mounted on the chassis or the stationary load support section, and a piston received within the cylinder. The piston may have an outer end remote from the cylinder mounted on a movable load support section whereby to move the movable load support section and its associated movable ramp section between the laterally expanded and laterally narrowed conditions.

The main load support may include a generally rectangular flat load bearing surface defined longitudinally between a leading end and a trailing end and transversely spaced lateral long sides thereof. Each said one pivoting ramp part may define part of a generally rectangular flat ramp surface between its leading end and its trailing end and between transversely spaced lateral sides.

The other extensible ramp part of each ramp section may be displaceable by translational movement in a direction rearward away from the one pivoting ramp part into an extended position for increasing the ramp surface and forming a ramp extending from the load support surface down to a road surface. The other extensible ramp parts may be displaceable in an opposite direction to retract them into a retracted position where the ramp surface is decreased.

The trailer vehicle may include a ramp extension drive means for driving said other extensible ramp parts into the extended position and then back into the retracted position.

The ramp extension drive means may be configured to drive all extensible ramp parts simultaneously between the retracted and extended positions so that they move together.

The extension drive means may comprise a hydraulic arrangement.

The main load support may include one load support arrangement for supporting one movable load support section on the stationary load support section when it is moved to the laterally expanded condition and then back to the laterally narrowed condition. The main load support may include another load support arrangement for supporting the other movable load support section on the stationary load support section when it is moved to the laterally expanded condition and then back to the laterally narrowed condition.

Each load support arrangement may also guide translational displacement of the movable load support section relative to the stationary central section of the main load support between the narrowed and expanded conditions.

Each load support arrangement may include at least one support arm extending laterally out from one of the stationary central body section and a said movable load support section, and a support member forming a passage, within which the support arm is received, defined by the other of the stationary central body section and a said main load support section.

Each load support arrangement may include a support arm on the stationary central load support section and a support member defining a passage on the movable load support section. Further each support arrangement may include a plurality of arms that are spaced apart along the length of the main load support.

The ramp arrangement may include one ramp support arrangement for movably supporting one movable ramp section on the stationary central ramp section when an associated movable load support moves from the laterally retracted to the laterally expanded condition, and a further support arrangement for similarly supporting the other movable ramp section on the stationary central ramp section.

Each ramp support arrangement may include a plurality of support arms that are spaced apart along the length of the stationary ramp section and that extend laterally outwards therefrom, and complementary support members on a said movable ramp section that are engaged with said arms whereby to movably support the movable ramp section.

The trailer vehicle may further include a plurality of road engaging wheels mounted on each side of the chassis.

According to another aspect of this disclosure there is provided a trailer vehicle for carrying a load vehicle that includes: a chassis; a main load support having a load bearing surface; and a ramp arrangement having a ramp body including one ramp part and another ramp part that define a traverse surface, said one ramp part being pivotally mounted on the main load support for pivoting the traverse surface of the ramp body relative to the load bearing surface of the main load support, and said other ramp part being mounted on the one ramp part and being displaceable relative to the one ramp part for increasing or decreasing the traverse surface of the ramp arrangement, wherein the main load support and the ramp arrangement are interchangeable between a laterally narrowed condition and a laterally expanded condition in which lateral side edges of the load support and the ramp arrangement are spaced laterally out of outer side edges of the chassis of the trailer vehicle.

The main load support and the ramp arrangement may be operatively coupled to each other such that lateral movement of the main load support between the expanded and narrowed conditions will cause, or does cause, a corresponding movement of the ramp arrangement between said narrowed and expanded conditions.

The ramp arrangement may be directly mounted on the main load support so that any lateral translational displacement is directly transmitted to the ramp arrangement.

The main load support may include a stationary load support section that is fixedly mounted on the chassis and at least one movable load support section that is movably mounted on the chassis and can be laterally displaced between said contracted and expanded conditions.

The ramp arrangement may include a stationary ramp section that resists lateral displacement relative to the chassis, and at least one movable side ramp section that is movable relative to the chassis, and can be laterally displaced between said contracted and expanded conditions.

The load support may include a central stationary load support section that is fixedly mounted on the chassis and two movable load support sections. One movable load support sections may be on one side of the central load support section, and the other movable load support section may be on the other side of the central load support section. The one and other movable load support sections can be laterally displaced between said contracted and expanded conditions.

The ramp arrangement may include a central stationary ramp section and two movable side ramp sections. One movable side ramp section may be on one side of the central ramp section and the other movable side ramp section may be on the other side of the central ramp section. The one and other movable side ramp sections can be laterally displaced between said contracted and expanded conditions.

The one ramp part may be pivotally mounted about a transverse pivot axis towards a rear end of the main load support so that the one ramp part is pivotally displaceable about the pivot axis. The one ramp part may be pivotally displaceable between an operative position in which the traverse surface inclines downwardly away from the load bearing surface, and a traveling position in which the traverse surface extends substantially horizontally outward away from the load bearing surface.

The ramp arrangement may be mounted on the main load support by having the central stationary ramp section of the one ramp part pivotally mounted to the stationary central section of the main load support. Further the movable side sections on each side of the central stationary ramp section may be pivotally mounted to the associated side sections of the main load support.

The trailer vehicle may include a drive means for driving each movable main load support section and each movable side ramp section between the laterally narrowed and laterally expanded conditions.

The drive means may include one hydraulic drive arrangement for driving one movable main load support section and its associated movable side ramp section, from the laterally narrowed to the laterally expanded condition, and then back to the laterally narrowed condition.

The drive means may include another hydraulic drive arrangement for similarly driving the other main load support section and its associated movable side ramp section, from the laterally narrowed to the laterally expanded condition, and then back to the laterally narrowed condition.

Each hydraulic drive arrangement may include a cylinder mounted on the chassis or the stationary load support section, and a piston received within the cylinder. The piston may have an outer end remote from the cylinder mounted on a movable main load support section whereby to move the movable main load support section and its associated movable side ramp section between the laterally expanded and laterally narrowed conditions.

The main load support includes an elongated load support body having a generally rectangular flat load bearing surface defined longitudinally between a leading end and a trailing end of the load support body and transversely spaced lateral long sides of the load support body.

The one ramp part in turn may include a ramp platform body defining a generally rectangular flat ramp platform traverse surface between its leading end and its trailing end and between transversely spaced lateral sides.

The one ramp part may include a hinging arrangement for mounting the ramp platform body about a transverse hinge axis towards the rear end of the elongated load support body. The hinging arrangement enables the ramp platform body to be hingedly displaceable about the hinge axis between an operative position in which the ramp platform traverse surface inclines downwardly away from the rear end of the load bearing surface, and a traveling position in which the ramp platform traverse surface extends away from the load bearing surface.

The other ramp part may include a plurality of ramp track members in the form of ramp extension sections that together define a track traverse surface between leading ends and trailing ends thereof and transversely spaced long sides thereof. The ramp extension sections may be displaceable by translational movement in a direction rearward away from the one ramp part into an extended position for increasing the effective traverse surface of the ramp arrangement. The ramp extension sections may also be displaceable in an opposite direction to retract the ramp extension sections into a retracted condition and decrease the effective ramp traverse surface.

The other ramp part may include two side ramp extension sections that are operatively mounted on the two movable side ramp sections on the ramp platform body of the ramp arrangement, such that these side ramp extension sections move laterally between the laterally extended and laterally narrowed conditions together with the associated movable side ramp section of the ramp platform body when it moves between the extended and narrowed conditions.

The other ramp part may also include a central stationary ramp extension section that is mounted on the central section of the ramp arrangement body, and which does not undergo any lateral movement during operation of the vehicle.

The central ramp extension section and the two side ramp extension sections form a continuous track traverse surface when the two side ramp extension sections are in the laterally narrowed condition. The two side ramp extension sections may be spaced outwardly of the central ramp section when the side ramp sections are in the laterally expanded condition.

The main load support may include one load support arrangement for supporting one movable side section on the load support when it is moved to the laterally expanded condition and then back to the laterally narrowed condition. The main load support may also include another load support arrangement for supporting the other side section on the load support body when it is moved to the laterally expanded condition and then back to the laterally narrowed condition.

Each load support arrangement may also guide translational displacement of the movable side section of the main load support relative to the stationary central section of the main load support between the narrowed and expanded conditions.

Each load support arrangement may include at least one support arm extending laterally out from one of the stationary central body section and a said movable side section, and a support member forming a passage defined by the other of the stationary central body section and a said side section, within which the support arm is received and with which the support arm is engaged.

In one convenient form of the disclosure each load support arrangement may include a support arm on the stationary central body section and a support member defining a passage on the movable side section, wherein the arm is received within the support passage.

Further in several forms of the disclosure, each support arrangement may include a plurality of arms that are spaced apart along the length of the main load support.

The ramp arrangement may include a ramp support arrangement for movably supporting one movable side ramp section on the stationary central ramp section. The ramp arrangement may include a further support arrangement for movably supporting the other movable side ramp section on the stationary central ramp section.

Each ramp support arrangement may include a plurality of support arms that are spaced apart along the length of the ramp platform body and that extend laterally outwards therefrom. Each support arrangement may also include complementary support members on the movable side ramp sections that are engaged with said arms.

The trailer vehicle may be supported on a vehicle support surface, and the one ramp part may include a ramp support towards its rear end for supporting the ramp platform body on a vehicle support surface when the ramp platform body is hingedly displaced to the operative position in which the ramp platform traverse surface inclines downwardly rearwards away from the rear end of the load bearing surface.

The ramp support may comprise a transversely extending ramp support wall projecting away from the ramp platform body towards the rear end thereof that defines a support wall base towards its free end for engaging the vehicle support surface.

The ramp platform support may be formed integrally with the ramp platform body. That is it may be formed as a part of the structure of the ramp platform body.

The ramp platform support may be engineered to provide load bearing support for a load to be borne by the ramp arrangement, e.g. when vehicles are loaded/unloaded from the trailer, at a point intermediate the main load support and the free end of the other ramp part. The support wall may be sized to support the trailing end of the ramp platform body at the correct height above the support surface when in the operative position

The ramp platform support may be a static or stationary fixed support that does not need to be moved into an operative position when it is used. That is it is not moved between operative and inoperative positions by a folding action or the like. It depends below the ramp platform body in the traveling position and when the ramp platform body is pivoted into the inclined or loading position, the downwardly depending ramp platform support is lowered into contact or engagement with the support surface.

The transverse support wall towards the rear end of the ramp platform body may be sized to support the rear end of the ramp platform body in a position in which the rear end of the ramp platform traverse surface is spaced above the vehicle support surface when the support wall base abuts the vehicle support surface. The ramp support wall may be sized to support the rear end of the ramp platform traverse surface spaced at least 0.4 m above the vehicle support surface when the support wall base, abuts the vehicle support surface.

Further, the hinging arrangement for mounting the ramp platform body toward the rear end of the main load support may be arranged so as to permit it to pivot relative to the main load support through at least 10 degrees between the traveling position and the operative or loading position, e.g. to pivot through a range of 13 to 17 degrees.

The ramp track members may be sized to project rearwards away from the ramp platform body so that the track traverse surface extends in a generally planar fashion between the rear end of the platform traverse surface and the vehicle support surface when the ramp platform body is in its inclined operative position. The ramp track members are sized to extend from the rear end of the ramp platform body to the support surface on which the trailer is supported, e.g. with the track traverse surface broadly in the same plane as the ramp platform traverse surface, when the ramp platform body is in the operative position and the ramp track members are in the extended position.

The ramp platform body may include a ramp track support surface over which the ramp track members are displaceable when displaced between the retracted and extended positions. The ramp track support surface may include two parallel transversely spaced sliding surfaces over which the two ramp track members are slidingly displaceable when displaced between the retracted and extended positions.

The ramp platform body may include a guiding arrangement for guiding the displacement of the ramp extension members between the retracted and extended positions. The guide arrangement may include transversely spaced guide formations and vertically spaced guide formations defining between them a track traveling path along which the displacement of the ramp extension members is guided between the retracted and extended positions.

The guide formations may be sized and shaped to be complementary to the outer sides of the ramp track members for snug sliding fitment of the ramp track members in the guide passages.

The other ramp part may include a bridging member extending transversely between the ramp track members for holding the ramp track members together in a fixed spaced relationship to each other. Each ramp track member may include an elongated generally flat substantially box-shaped body having a longitudinally tapered rear end portion defining a transverse taper end portion face at a taper angle that enables the taper end portion face to lie flat on the vehicle support surface, in use.

The ramp arrangement may include a ramp platform drive means for driving the ramp platform pivotally about the hinge axis between the traveling and operative positions. The ramp platform drive means may include a hydraulic drive means, e.g. in the form of two laterally spaced hydraulic actuators, that are mounted between an undercarriage of the trailer vehicle and the ramp platform body, for displacing the ramp platform pivotally about the hinge axis.

Similarly, the trailer may include a ramp track member drive means for displacing the ramp track members towards and away from the ramp platform body between the extended and retracted positions along the ramp track member traveling path. The ramp track member drive means may include a hydraulic actuator mounted between the ramp platform body and the bridging member extending transversely between the ramp track members.

The ramp track member drive means may be actuable independently of the ramp platform drive means.

The trailer vehicle may also include a locking arrangement for locking the ramp platform body in the traveling position in which the ramp platform traverse surface extends horizontally and generally planar with the load bearing surface. The locking arrangement may also be able to lock the ramp platform body in the operative position in which the ramp platform traverse surface inclines downwardly away rearwards from the rear end of the load bearing surface.

The locking arrangement may include at least two vertically offset transversely open apertures defined on the vehicle, e.g. a rear end of the undercarriage of the vehicle, and that are associated with the inclined operative position and the horizontal traveling position of the ramp platform body respectively, a transverse open aperture on the ramp platform body that can be aligned with each of said transversely open apertures on the vehicle, and a locking pin transversely retractably displaceable into the apertures at the respective positions for positively locking the ramp platform body to the vehicle in either one of said operative and traveling positions.

The trailer vehicle may include at least one user controller unit interfaced with a hydraulic system of the trailer vehicle for controlling the hydraulic actuators and the locking arrangement.

Yet also, the undercarriage of the trailer vehicle may include two transversely space parallel elongated support beams extending longitudinally between a rear end and a front end of the main load support body.

The elongated load support body may also include a raised support body portion toward a leading end of the load support body.

The trailer vehicle may be a heavy duty trailer and may include a coupling arrangement for coupling to a fifth-wheel hitch of a tractor vehicle.

The vehicle may have its own motive means for driving it on a road.

The vehicle may be a truck and the main load support may be a flat load platform.

Instead the vehicle may be a utility vehicle and the main load support may be a utility tray. Yet further the vehicle may be a trailer for being towed by a car, e.g. a small trailer.

The road going vehicle may have a main load support within an enclosed goods carrying compartment. The main load support is not required to be open to the outside air.

According to another aspect of this disclosure there is provided a ramp arrangement for a vehicle having a chassis, and also a main load support having a load bearing surface, the ramp arrangement including a ramp arrangement having a ramp body including one ramp part and another ramp part that define a traverse surface, said one ramp part being pivotally mounted on the main load support for pivoting the traverse surface of the ramp body relative to the load bearing surface of the main load support, and said other ramp part being mounted on the one ramp part and being displaceable relative to the one ramp part for increasing or decreasing the traverse surface of the ramp arrangement, wherein the main load support and the ramp arrangement are interchangeable between a laterally narrowed condition and a laterally expanded condition in which lateral side edges of the load support and the ramp arrangement are spaced laterally out of outer side edges of the chassis of the trailer vehicle.

The ramp arrangement may include any one or more of the features of the ramp arrangement of the trailer vehicle defined in the first aspect of the disclosure above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A trailer vehicle and a ramp arrangement in accordance with this disclosure may manifest itself in a variety of forms. It will be convenient to hereinafter describe at least one embodiment of the disclosure in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the disclosure how to carry the disclosure into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings:

Figure 1 is a three dimensional view of a trailer vehicle with a ramp arrangement according to the prior art;

Figure 2 is a three dimensional view of a trailer vehicle in accordance with one aspect of the disclosure having a ramp arrangement;

Figure 3 is a side view of the trailer vehicle in Figure 2 with the ramp arrangement in a raised traveling position;

Figure 4 is a side view of the trailer vehicle with the ramp arrangement in a lowered operative position for enabling vehicles to be driven onto or driven off the trailer vehicle;

Figure 5 is a top plan view of a ramp platform body forming part of the ramp arrangement;

Figure 6 is a sectional side view along line VI-VI in Figure 5;

Figure 7 is top plan view of another part of the ramp platform body showing it attached to chassis support beams of the trailer vehicle;

Figure 8 is a sectional side view along line VII-VII in Figure 7;

Figure 9 is a bottom plan view of ramp track members forming part of the ramp arrangement;

Figure 10 is a sectional side view of one of the ramp track members in Figure 9 taken along line X-X;

Figure 11 is a sectional side view of a rear end portion of the trailer vehicle and the ramp arrangement;

Figure 12 is a rear end view of the ramp platform body;

Figure 13 is a view of a longitudinal section of a rear part of the trailer vehicle and part of the ramp platform body;

Figure 14 is a transverse sectional view of the rear part of the trailer vehicle and part of the ramp platform body in Figure 15 taken along line XIV-XIV;

Figure 15 is a bottom view of the part in Figure 13 showing a locking arrangement for the ramp platform body;

Figure 16 is side view of a rear end part of a chassis support beam;

Figure 17 is a sectional view of the part in Figure 16 taken along line XVII-XVII; and

Figure 18 is a side view of a rear end of the trailer and the ramp platform showing controls mounted on a side of the ramp platform;

Figure 19 is a three dimensional view of a trailer vehicle in accordance with another aspect of the disclosure showing a main load support and a ramp arrangement in a laterally narrowed condition and in a downwardly extending operative position;

Figure 20 is a three dimensional view of a trailer vehicle of Fig 19 showing the showing the main load support and the ramp arrangement in a laterally expanded condition and a downwardly extending operative position;

Fig 21 is a three dimensional view of a trailer vehicle of Fig 19 showing the main load support and the ramp arrangement in a laterally widened condition and the ramp arrangement in a horizontally extending traveling position and a retracted condition;

Fig 22 is a three dimensional view of a trailer vehicle of Fig 19 showing the main load support and the ramp arrangement in a laterally narrowed condition, and the ramp arrangement in a horizontally extending traveling position and in an extended condition;

Fig 23 is a three dimensional view of a trailer vehicle of Fig 19 showing the main load support and the ramp arrangement in a laterally widened condition, and with the ramp arrangement in a horizontally extending traveling position and an extended condition; and

Figures 24 to 26 show respectively a side view, a bottom plan view and a side view of the trailer vehicle of Fig 19.

In Figure 1 reference numeral 10 refers generally to a prior art trailer vehicle for a heavy duty truck for over the road hauling of heavy loads.

The trailer vehicle 10 includes a loading deck 16 that can be used for transporting load vehicles such as cars, tractors, bobcats, forklift trucks, front end loaders, bull dozers and other ground moving equipment.

These ground engaging load vehicles or pieces of equipment as described above, need to be loaded onto and unloaded from the loading deck 16. Conveniently the trailer vehicle 10 includes a driving ramp arrangement, generally indicated by reference numeral 14, at the tail of the trailer 10 over which the load vehicle can be driven to both load it on the trailer 10 and unload it from the trailer 10.

The driving ramp arrangement 14 includes two parallel ramp track members 18, 20 having traverse surfaces, one towards each side of the vehicle 10. As shown the two parallel ramp track members are operatively able to pivot (see arrows 22) between a downwardly inclined operative position extending rearwards away from the vehicle 10 and a vertically upstanding inoperative stowed position or traveling position.

In the stowed position the two ramps tracks 18, 20 project vertically upward from the trailer 10 when the trailer 10 is driven along a road, so that traverse surfaces of the ramp tracks 18, 20 face the forward traveling direction. This creates a high drag coefficient and causes a high level of drag resistance particularly when the trailer 10 is traveling along the road at typical road speeds.

Figure 2 shows a trailer vehicle 22.

The trailer vehicle 22 is for a heavy duty truck having a tractor (not shown) for towing the trailer vehicle 22 over a vehicle support surface such as a road. The trailer 22 has a main load support in the form of a loading deck, generally indicated by reference numeral 24.

The trailer 22 also includes a ramp arrangement 12 having a ramp body 30 including at least two parts 32, 34 that together define a traverse surface 36 and a trailer undercarriage.

The one ramp part 32 is pivotally mounted on the main load support 26 for pivoting the traverse surface 36 of the ramp body 30 relative to the load bearing surface 28 of the loading deck 24. The other ramp part 34 is mounted on the one ramp part 32 and is displaceable relative to the one ramp part 32 for increasing or decreasing the effective traverse surface 36 of the ramp body 30.

The loading deck 24 includes an elongated generally rectangular flat load bearing surface or floor 28 defined longitudinally between a leading end and a trailing end of the loading deck 24 and transversely spaced lateral long sides of the loading deck 24.

The one ramp part 32 includes a generally rectangular ramp platform body 38 defining a generally flat ramp platform traverse surface 36.1 extending between its leading end and trailing end and between transversely spaced lateral sides. The one ramp part 32 also includes a hinging arrangement 40 for mounting the ramp platform body 38 about a transverse hinge axis 42 towards the rear end of the loading deck 24. Thus, the ramp platform body 38 is hingedly displaceable about the hinge axis 42 between an operative position in which the ramp platform traverse surface 36.1 inclines (see Figures 2 and 4) downwardly in a rearward direction away from the rear end of the loading deck 24 and a traveling position in which the ramp platform traverse surface 36.1 extends generally horizontally (see Figure 3) such that it is in plane with the load bearing surface 28 of the loading deck 24.

In this embodiment, the hinging arrangement 40 mounts the ramp platform body 38 on the loading deck 24 in such a way that it permits the ramp platform body 38 to pivot relative to the loading deck 24 through at least 10 degrees between the inclined operative position and the horizontal traveling position. Typically the ramp platform body pivots through a range of 13 to 17 degrees. The hinging arrangement 40 includes hinge pins 48 and cooperating hinge sleeves 50 that are mounted towards adjacent edges of the ramp body 38 and the chassis support beams 52 of the trailer undercarriage.

The one ramp part 32 includes a ramp support 44 towards its rear end for supporting the ramp platform body 38 on the vehicle support surface when the ramp platform body 38 is hingedly displaced to the operative position in which the ramp platform traverse surface 36.1 inclines downwardly rearwards away from the rear end of the load bearing surface 28. The ramp support 44 includes a transverse support wall towards the rear end of the ramp platform body 38 that projects away from the ramp platform body 38 and has a base 40 at its free end for engaging the vehicle support surface. The support wall 44 is formed integrally with the ramp platform body 38 as a part of the structure of the ramp platform body 38 so it depends down below the ramp platform body 38. Also it is permanently fixed in position and does not need to be moved out or folded out when it is used to support the ramp platform body 38.

The transverse support wall 44 towards the rear end of the ramp platform body 38 is sized to have a vertical height so that, when the ramp platform body 38 is supported on the vehicle support surface by the support wall 44, the ramp platform traverse surface 36.1 is positioned above the vehicle support surface, e.g. at least 0.4 m above the vehicle support surface.

In the illustrated embodiment the other ramp part 34 includes two laterally spaced elongated ramp track members 52,54 defining track traverse surfaces 36.2 between leading ends and trailing ends and transversely spaced long sides thereof. The ramp track members 52, 54 are displaceable in a translational fashion rearward away from the ramp platform body 38 for increasing the effective traverse surface 36 of the ramp body 38 in a rearwards direction.

Thus, the track traverse surfaces 36.2 of the ramp track members 52, 54 overlap the platform traverse surface 36.1 when the ramp track members are largely received in the ramp platform body 38 in the retracted position, and are exposed when the ramp track members 52, 54 are displaced rearwards away from the ramp platform body 38 into an extended position to increase the effective traverse surface 36. The effective traverse area is thus the sum of the platform traverse surface 36.1 and the portion of the track traverse surface 36.2 that projects out of the ramp platform body 38.

The ramp platform body 38 is generally box-shaped and includes an interior defined between a top wall and transversely spaced side walls. The ramp track members 52, 54 are received within the interior of the ramp platform body 38 when it is retracted so that the track traverse surfaces 36.2 overlap substantially completely with the ramp platform traverse surface 36.1. The ramp track members 52, 54 are operatively able to displace in a translational fashion from a retracted position rearward away from the ramp platform body 38 to an extended position for increasing the effective traverse surface 36 of the ramp body 30

The ramp platform body 38 includes a ramp track support surface, for vertically supporting the ramp tracks, over which the ramp track members 52, 54 are displaceable when displaced between the retracted and extended positions.

The ramp platform body 38 includes a guiding arrangement, generally indicated by reference numeral 56, for guiding the displacement of the ramp track members 52, 54 between their retracted and extended positions. The guide arrangement 56 includes transversely spaced guide formations and vertically spaced guide formations formed by structural parts of the ramp platform body 38. The guide formations define guide passages forming ramp track member travel paths (see arrow 58) along which the displacement of the ramp track members 52, 54 are guided between the retracted and extended positions. The guide formations also form rearward openings 60 through which the ramp track members 52, 54 pass when displaced to the extended position.

To this end, the guide formations 56 are sized and shaped to be complementary to lateral outer sides of the ramp track members 52, 54 for snug sliding fitment of the ramp track members in the guide passages. Also, the ramp track support surfaces are formed by the guide formations over which the two ramp track members 52, 54 are slidingly displaceable when displaced between the retracted and extended positions.

Each ramp track member 52, 54 includes an elongated generally flat box-shaped body 62 having a longitudinally tapered rear end portion 66 defining a transverse taper portion face 64 at a taper angle that enables the taper end portion face 64 to lie flat on the vehicle support surface, in use.

The other ramp part 34 also includes a bridging member 68 in the form of a brace extending transversely between the ramp track members 52, 54 for holding the ramp track members 52, 54 together in a fixed spatial relationship to each other. The brace 68 includes a mounting flange 70 projecting forwardly from a position intermediate transverse ends of the brace 68.

The trailer 22 also includes a ramp platform drive means 72 for driving the ramp platform body 38 pivotally about the hinge axis 42. The ramp platform drive means 72 includes two laterally spaced hydraulic actuators or rams 74 mounted between mounting brackets 76 provided on the undercarriage of the trailer vehicle 22 and mounting brackets 78 provided on the ramp platform body 38, for displacing the ramp platform body 38 pivotally about the hinge axis.

Further, the trailer 22 includes drive means 80 for the ramp track members 52, 54 in the form of a hydraulic actuator or ram for displacing the ramp track members 52, 55 along the ramp member traveling path 58 between the extended and retracted positions. The trailer includes two forwardly projecting transversely spaced arms 82, 84 and a brace member 86 extending there between. The hydraulic actuator 80 is mounted between the associated brace member 86 and mounting flange 70 projecting from the brace 68 of the ramp track members 52, 54.

The trailer 22 includes a user control arrangement 88 for controlling the activation of the hydraulic actuators 74 and 80 independently, so that the ramp track members 52, 54 and the ramp platform body 38 are controllable independently from each other. The control arrangement 88 includes control pendants 90 that are interfaced with the hydraulic system of the trailer and that are carried on a side of the trailer 22 near the rear thereof.

The trailer 22 further includes a locking arrangement, generally indicated by reference numeral 92, for releasably locking the ramp platform body 38 in either one of the inclined or horizontal positions. The locking arrangement 92 includes two vertically offset transversely open apertures 94 defined by a rear end of the support beams 52 of the trailer 22 that are associated with the inclined position and the horizontal position of the ramp platform body 38 respectively. The ramp platform body 38 includes vertically extending locking brackets 39 that define an aperture 98 there through and that are displaceable with the ramp platform body 38 for registering with either one of the apertures 94 in the inclined or horizontal positions, as the case may be. The locking arrangement also includes a locking pin 100 for passing through the registering aperture 98 in the bracket and the aperture 94 in the beams 52. The locking pin 100 is controlled by retraction or extension from a hydraulic booster unit 102 for positively locking the ramp platform body 38 relative to the undercarriage of the trailer 22.

The trailer vehicle 22 also includes a raised support body portion 104 towards a leading end of the load support body 24. This includes a fifth wheel for pivotally mounting over the rear axle of a towing rig in the usual way.

In use, if a user wishes to load a ground engaging load vehicle such as a earthmoving machine on the loading bed 24 of the trailer 22, a user selects the appropriate control from the controls 90.

This retracts the pin 100 out of the locking pin apertures 98, 94 so that the platform body 38 is free to pivot about the hinge axis 42 relative to the loading deck 24.

The user then actuates the hydraulic rams 74 of the ramp body drive arrangement 72 (using the controls 90) for displacing the ramp platform body 38 from the traveling to the operative position. To do this the ramp platform body 38 is pivoted towards the vehicle support surface until the base 46 of the support wall 44 engages the vehicle support surface. At this stage, the associated locking pin apertures 94, 98 register with each other and the locking pin 100 is inserted into the registering holes for holding the ramp platform body 38 in its inclined position. The ramp platform traverse surface 36.1 of the ramp platform body now inclines rearwards from the load bearing surface 28. However the ramp platform traverse surface 36.1 remains spaced away from the vehicle support surface or ground.

The user then selects the appropriate control 90 and activates the hydraulic ram 80 of the track member drive arrangement 80 which causes the ramp track members 52, 54 to be displaced in a translational fashion out of the ramp platform body 38. The track members 52, 54 are displaced away from the ramp body 38 until their wedge portions 66 and particularly the faces 64 thereof reach the support surface.

An earthmoving machine to be loaded on the trailer can now be driven up the ramp arrangement 12 over the effective traverse surface 36 comprising platform traverse surface 36.1 and the track traverse surface 36.2 onto the loading deck 24. Once the earthmoving machine is loaded onto the deck 24, the user can retract the hydraulic ram 80 so that the ramp track members 52, 54 are retracted into the ramp platform body 38. The locking pin 100 is then retracted and the ramp platform body is displaced hingedly to its horizontal position. Thereafter the locking arrangement is activated by the user, to lock the ramp platform body 38 in its horizontal position. The above steps are repeated when the time comes to offload the earthmoving machine.

Figs 19 to 26 illustrate a trailer vehicle in accordance with an embodiment of the disclosure. As the vehicle has some similarities with the vehicle illustrated in Figs 2 to 18 the following description will focus on the differences between this embodiment and the earlier embodiment. Further unless otherwise indicated the same reference numerals will be used to refer to the same components. A significant feature of this embodiment is that the main load support and the ramp arrangement are interchangeable between a laterally narrowed condition (Fig 19) and a laterally expanded condition (Fig 20). In the expanded condition the lateral side edges of the load support 26 and the lateral side edges of the ramp arrangement 12 are spaced laterally outward of outer side edges of the wheels of the trailer vehicle 22. They are also spaced laterally outward of the underlying chassis of the trailer vehicle 22.

The main load support 26 and the ramp arrangement 12 are operatively coupled to each other in such a way that movement of the main load support 26 between the expanded and narrowed conditions will similarly cause the ramp arrangement 12 to be moved between said narrowed and expanded conditions. In the illustrated embodiment the ramp arrangement 12 is directly mounted on the load support 26 such that movement of the main load support 26 causes a corresponding movement of the ramp arrangement 12 between said narrowed and expanded conditions.

The construction of the main load support 26 and the ramp arrangement 12 that facilitates this lateral movement will now be described in more detail.

The load support 26 comprises a stationary load support section 120 that is fixedly mounted on the chassis and two movable sections 122, 124, one on each side of the central section 120 that can be laterally displaced between said contracted and expanded conditions. Correspondingly the ramp arrangement 12 includes a central stationary section 130 that resists lateral displacement relative to the chassis and two laterally movable sections 132, 134, one on each side of the stationary central section 130 that can be laterally displaced between said contracted and expanded conditions.

As described above with reference to Figs 2 to 18 the first ramp part 32 is pivotally mounted to the main load support 26 about a transverse pivot axis towards a rear end thereof so that the ramp part 32 is pivotally displaceable between a downwardly inclined operative position and a horizontally extending traveling position, in the same plane as the load bearing surface.

In the embodiment in Figures 19 to 23 the ramp arrangement is mounted on the main load support 26 by having the central stationary section 130 of the first ramp part 32 pivotally mounted to the stationary central section 120 of the main load support 26. Similarly the movable side sections 132,134 on each side of the central stationary section 130 are pivotally mounted to their associated movable side sections 122, 124 of the main load support 26.

The trailer vehicle 22 includes a drive means in the form of two or more drive arrangements 136, 138 for driving the movable sections 122, 124 of the main load support 26 between the laterally narrowed and laterally expanded conditions. This in turn displaces the corresponding sections 132, 134 of the ramp arrangement 12 that are operatively coupled to their associated load support sections 122, 124 to also be displaced between the laterally narrowed and expanded conditions.

One drive arrangement 136 includes at least one hydraulic drive arrangement for driving one side section 122 of the main load support 26 from the laterally narrowed to the laterally expanded condition and back again. The other drive arrangementl 38 also includes at least one hydraulic drive arrangement for driving the other side section 124 of the main load support 26 from the laterally narrowed to the laterally expanded condition and back again.

Fig 25 in particular shows some of the underlying features of the trailer vehicle 22 described above with reference to Figs 19 to 26. In Fig 25 the hydraulic drive arrangement for driving one movable section of the load support is shown by reference numerals 136 and the hydraulic drive arrangement for driving the other movable section of the load support is shown by reference numeral 138.

In the illustrated embodiment the movable side section 120 is driven by two hydraulic drive arrangements that are axially spaced apart from each other in the longitudinal direction of the main load support 26. Similarly the other movable side section 122 is driven by two hydraulic drive arrangements that are axially spaced apart from each other in the longitudinal direction of the main load support 126.

Each hydraulic arrangement includes a cylinder mounted on the chassis and a piston received within the cylinder and having an end mounted on the side section, whereby to move the associated side section 122, 124 of the load support 26 and the ramp arrangement 12 between the laterally expanded and laterally narrowed conditions.

As described above with reference to Figs 2 to 18, the main load support 12 includes an elongated load support body having a generally rectangular flat load bearing surface.

The first ramp part 32 includes a ramp platform body 38 defining a generally rectangular flat ramp platform traverse surface 36.1 between its leading end and its trailing end. Also, the first ramp part 32 includes a hinging arrangement for mounting the ramp platform body about a transverse hinge axis towards the rear end of the elongated load support body 26. This facilitates hinged displacement of the ramp platform body 38 between an inclined operative position and a horizontally extending traveling position.

The second ramp part 34 is mounted on the ramp platform body 38 and comprises three ramp track members that are in the form of three ramp extension sections 140, 142, and 144. The three ramp track sections collectively define a track traverse surface 36.2 between leading ends and trailing ends thereof. The ramp extension sections 140, 142, and 144 are received within the ramp platform body 38 in a retracted position in which the track traverse surface 36.2 overlaps substantially completely with the ramp platform traverse surface 36.1. The ramp extension sections 140, 142, and 144 are able to be displaced by translational movement by a ramp extension member drive means in a rearward direction out of the ramp platform body 38 to an extended position to increase the effective traverse surface 36 of the ramp arrangement 12.

The three ramp extension sections include one central ramp extension section 140 and two side ramp extension sections 142 and 144 disposed on each side of the central ramp extension section 140.

The central ramp extension section 140 is mounted on the stationary central section 130 of the ramp arrangement 12 and like the central ramp extension section 130 does not undergo any lateral movement.

Each of the side ramp extension sections 142, 144 is operatively mounted to the two movable side sections 132, 134 of the ramp platform body 38 and can be received within the ramp platform body 38 in the retracted position. That is the side ramp extension section 142 is mounted on and can be received within the side section 132 of the ramp platform body 38. The same arrangement applies on the other side. These side ramp extension sections 142, 144 thus move laterally between the laterally extended and laterally narrowed conditions in sympathy with and together with the associated movable side section 132,134 of the ramp platform body 38.

In the illustrated embodiment the central ramp extension section 140 and the two side ramp extension sections 142, 144 form a continuous surface when the load support 26 and the ramp arrangement 12 is in the laterally narrowed condition. The side ramp extension sections 142, 144 are spaced outwardly of the central ramp section 140 when the side ramp extension sections 142, 144 are in the laterally expanded condition.

The main load support includes a load support arrangement shown generally by numeral 150 for supporting one movable load support side section 122 on the stationary load support section 120 when it is moved to the laterally expanded condition.

It also includes another load support arrangement 152 for supporting the other movable load support section 124 on the stationary load support section 122 when it is moved to the laterally expanded condition and back again.

Each load support arrangement 150, 152 includes a plurality of support arms 156 on the stationary central body section 120 and corresponding support members defining a passage on the movable side section (not shown), wherein each arm 156 is received within the support passage.

The ramp arrangement 12 also includes a ramp support arrangement 160 for supporting the movable side ramp section 132 on the stationary central ramp section 130. It also includes a further support arrangement 162 for movably supporting the other movable side ramp section 134 on the stationary central ramp section 130.

Each ramp support arrangement 160, 162 includes a plurality of support arms 166 that are spaced apart along the length of the ramp platform body 38 and that extend laterally outwards therefrom and complementary support members defining passages ( not shown) on the movable side ramp sections that are engaged with said arms 166.

In use the trailer vehicle of Figs 19 to 26 can be used in transport load vehicles from one place to another.

In a typical road traveling position, the ramp platform body 38 projects in a horizontally extending fashion away from the main load support body. The ramp extension sections 140, 142, 144 are received within the ramp platform body 38 in the retracted condition.

When it is desired to a load vehicle onto the load support body or unload a vehicle from the load support body, the ramp platform body 38 is pivoted about the load support body into a downwardly extending operative position. Further the central and side ramp extension members 140, 142, 144 are displaced out of the ramp platform body 38 into their extended position. This forms a traverse surface 36 made up of the ramp platform traverse surface 36.1 and a track traverse surface 36.2 that extends from the rear end of the load support body down to the ground. If the load vehicle being loaded or unloaded, has ground engaging formations of normal road lane width then the load support 26 and the ramp arrangement 12 is retained in its laterally narrowed condition. In this condition the movable sections of respectively the load support 26, the ramp platform body 38 and the second ramp part for extending the ramp are arranged so that they lie up against the stationary sections 120, 130 and 140 of said load support, the ramp platform body and the second ramp part. This forms a continuous traverse surface as shown in Fig 19.

If a load vehicle has wider ground engaging formations than normal road lane width then the load support 26, and the ramp arrangement 12 can be moved to the laterally expanded condition. This is done by means of the hydraulic drive arrangements 136, 138 driving respectively left and right movable load support sections 122, 124. The corresponding movable sections 132, 134 of the ramp platform body 38 are hingedly mounted to the moveable load support sections 122, 124 thereby moving them also to the laterally expanded condition. The movable ramp extension members 132,134 that are mounted on the associated ramp platform body sections are also thereby moved to the expanded condition which is shown in Fig 20.

Further the trailer vehicle 22 described above can be arranged in a number of different ways when it is in the traveling condition with the ramp arrangement projecting substantially horizontally away from the load platform body.

Fig 21 shows the trailer vehicle in the traveling position with the main load support 26 and the ramp arrangement 12 in the laterally widened condition. In this Fig the ramp extension sections 140, 142, 144 of the second ramp part are in the retracted position received within the ramp platform body 38.

Fig 22 shows the trailer vehicle in the same arrangement as Fig 21 with the ramp extension sections 140, 142, 144 in the extended position instead of the retracted position. This provides a load deck for receiving a load vehicle of additional length when compared with that in Fig 21 as well as providing additional width when compared with longitudinally and laterally fully retracted conditions.

Fig 23 shows the ramp extension sections 140, 142, 144 in the extended position instead of the retracted position as in Fig 21. Flowever in Fig 23 the load support 12 and the ramp arrangement 26 is in the laterally narrowed condition.

It will therefore readily be appreciated that the trailer vehicle can be arranged in a number of ways with the ramp arrangement both in the traveling and operative conditions.

An advantage of the trailer vehicle described above with reference to the drawings is that the load support surface and the traverse surface of the ramp arrangement can be laterally widened to accommodate a wider load vehicle if this is required. The main load support can support the load while it is in a traveling mode being transported on the trailer vehicle. Importantly the ramp arrangement provides a widened ramp traverse surface over which a load vehicle can be displaced to load it on the main load support and also to unload it from the main load support. This is advantageous in some applications where heavy load vehicles with wheel spacing that is wider than that for conventional road going vehicles are used.

Another advantage of the trailer vehicle described above is that the various sections of the ramp arrangement are directly mounted on the associated sections of the main load support and thus they move (or stay stationary) together with the associated section of the main load support. Thus a single drive arrangement can be used to drive each side section of the main load support and this also effects corresponding movement of the side sections of the associated side section of the ramp arrangement with a fine tolerance. The driving arrangement on the main load support can be used to efficiently and effectively move all of the side sections of the load support, the ramp platform body and the section of the other ramp part with a fine tolerance between the narrowed and widened conditions.

Yet another advantage of the trailer vehicle described above is that each section of the further ramp part is mounted on and at least partly received within the corresponding section of the one ramp part. It thus moves laterally together with that section of the one ramp part. Also the associated section of the one ramp part guides the movement of the associated section of the other ramp part and vertically supports the section of the other ram p part.

Further the width of the load support surface and the ramp arrangement can be adjusted to suit the ground engaging formations, e.g. wheels, of the load vehicle that is being carried. This adjusted position may be at any point intermediate the laterally narrowed condition and the laterally expanded conditions. The hydraulic cylinders permit infinite adjustment between these two positions as distinct from spacing at discrete spaced intervals between the laterally narrowed and expanded conditions.

Another advantage of the trailer vehicle described above is that the ramp arrangement can be used to provide a load surface having a more flexible capability when the ramp arrangement is in a horizontally extending load carrying position. For example the sections of the other ramp part can be fully extended out of the associated sections of the ramp platform body providing a load surface of increased length. Further the side sections of the main load support, the ramp platform body and the other ramp part can be laterally displaced to the laterally expanded conditions. This provides a load support of increased length and increased width for carrying a load vehicle, e.g. of increased width and length, in the horizontally extending traveling position.

It will of course be realized that the above has been given only by way of illustrative example of the disclosure and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the disclosure as is herein set forth.

Claims (20)

1. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

   1. A trailer vehicle for carrying a load that includes: a chassis; a main load support having a load bearing surface mounted on the chassis, the main load support includes a central stationary load support section that is fixedly mounted on the chassis and two movable load support sections, one on each side of the central load support section that can be slidably displaced in translational fashion between a laterally narrowed condition and a laterally expanded condition; and a ramp arrangement for forming a ramp surface from the load bearing surface to a road surface, the ramp arrangement including a central stationary ramp section and two movable ramp sections, one on each side of the central ramp section, each movable ramp section is directly mounted in pivotal fashion on its associated movable load support section so that the load support section and ramp section move together between the laterally narrowed and laterally expanded conditions, and wherein each movable ramp section includes one pivoting ramp part and another extensible ramp part, said one pivoting ramp part being proximate to and pivotally mounted on its associated movable load support section and the other extensible ramp part being mounted on the one pivoting ramp part, the other extensible ramp part being slidably extendable in translational fashion relative to the one pivoting ramp part to increase the ramp surface and being slidably retractable to decrease the ramp surface.
2. 2. A trailer vehicle according to claim 1, wherein the central stationary ramp section is pivotally mounted on the central stationary load support section, and the stationary ramp section includes one pivoting ramp part and another extensible ramp part like the corresponding parts of the movable ramp sections.
3. 3. A trailer vehicle according to claim 1 or claim 2, wherein the load support and the ramp arrangement are positioned closely adjacent to each other in the laterally narrowed condition and lateral side edges of the load support and the ramp arrangement are spaced laterally out beyond outer side edges of the chassis of the trailer vehicle in the laterally expanded condition.
4. 4. A trailer vehicle according to any one of claims 1 to 3, wherein each said pivoting ramp part is pivotally mounted about a transverse pivot axis towards a rear end of the main load support, and is pivotally displaceable about the pivot axis between an operative position in which the traverse surface inclines downwardly away from the load bearing surface, and a traveling position in which the traverse surface extends substantially horizontally outward away from the load bearing surface.
5. 5. A trailer vehicle according to any one of claims 1 to 4, including a drive means for driving each movable main load support section and its associated movable side ramp section between the laterally narrowed and laterally expanded conditions.
6. 6. A trailer vehicle according to claim 5, wherein the drive means includes one hydraulic drive arrangement for driving one movable load support section together with its associated movable ramp section, from the laterally narrowed to the laterally expanded condition and back to the laterally narrowed condition, and another hydraulic drive arrangement for similarly driving the other movable load support section together with its associated movable ramp section, from the laterally narrowed to the laterally expanded condition and back to the laterally narrowed condition.
7. 7. A trailer vehicle according to claim 6, wherein each hydraulic arrangement includes a cylinder mounted on the chassis or the stationary load support section, and a piston received within the cylinder and having an outer end remote from the cylinder mounted on a movable load support section whereby to move the movable load support section and its associated movable ramp section between the laterally expanded and laterally narrowed conditions.
8. 8. A trailer vehicle according to any one of claims 1 to 7, wherein the main load support includes a generally rectangular flat load bearing surface defined longitudinally between a leading end and a trailing end and transversely spaced lateral long sides thereof, and each said one pivoting ramp part defines part of a generally rectangular flat ramp surface between its leading end and its trailing end and between transversely spaced lateral sides.
9. 9. A trailer vehicle according to any one of claims 1 to 8, wherein the other extensible ramp part of each ramp section is displaceable by translational movement in a direction rearward away from the one pivoting ramp part into an extended position for increasing the ramp surface and forming a ramp extending from the load support surface down to a road surface, and the other extensible ramp parts are displaceable in an opposite direction to retract them into a retracted position where the ramp surface is decreased.
10. 10. A trailer vehicle according to claim 9, including a ramp extension drive means for driving said other extensible ramp parts into the extended position and then back into the retracted position.
11. 11. A trailer vehicle according to claim 10, wherein the ramp extension drive means is configured to drive all extensible ramp parts simultaneously between the retracted and extended positions so that they move together.
12. 12. A trailer vehicle according to claim 10 or claim 11, wherein the extension drive means comprises a hydraulic arrangement.
13. 13. A trailer vehicle according to any one of claims 1 to 12, wherein the main load support includes one load support arrangement for supporting one movable load support side section on the stationary load support section when it is moved to the laterally expanded condition and then back to the laterally narrowed condition, and another load support arrangement for supporting the other movable load support side section on the stationary load support section when it is moved to the laterally expanded condition and then back to the laterally narrowed condition.
14. 14. A trailer vehicle according to claim 13, wherein each load support arrangement also guides translational displacement of the movable side section of the main load support relative to the stationary central section of the main load support between the narrowed and expanded conditions.
15. 15. A trailer vehicle according to claim 13 or claim 14, wherein each load support arrangement includes at least one support arm extending laterally out from one of the stationary central body section and a said movable side section, and a support member forming a passage within which the support arm is received, defined by the other of the stationary central body section and a said side section.
16. 16. A trailer vehicle according to claim 15, wherein each load support arrangement includes a support arm on the stationary central load support section and a support member defining a passage on the movable side section, and each support arrangement includes a plurality of arms that are spaced apart along the length of the main load support.
17. 17. A trailer vehicle according to any one of claims 1 to 16, wherein the ramp arrangement includes one ramp support arrangement for movably supporting one movable ramp section on the stationary central ramp section when an associated movable load support moves from the laterally retracted to the laterally expanded condition, and a further support arrangement for similarly supporting the other movable ramp section on the stationary central ramp section.
18. 18. A trailer vehicle according to claim 17, wherein each ramp support arrangement include a plurality of support arms that are spaced apart along the length of the stationary ramp section and that extend laterally outwards therefrom, and complementary support members on a said movable ramp section, that are engaged with the arms whereby to movably support the movable ramp section.
19. 19. A trailer vehicle according to any one of claims 1 to 18, further including a plurality of road engaging wheels mounted on each side of the chassis.
20. 20. A vehicle for carrying a load that includes: a chassis; a main load support having a load bearing surface mounted on the chassis, the main load support includes a central stationary load support section that is fixedly mounted on the chassis and two movable load support sections, one each on each side of the central load support section that can be slidably displaced in translational fashion between a laterally narrowed condition and a laterally expanded condition; and a ramp arrangement for forming a ramp surface from the load bearing surface to a road surface, the ramp arrangement including a central stationary ramp section and two movable ramp sections, one on each side of the central ramp section, each movable ramp section is directly mounted in pivotal fashion on its associated movable load support section so that the load support section and ramp section move together between the laterally narrowed and laterally expanded conditions, and wherein each movable ramp section includes one pivoting ramp part and another extensible ramp part, said one pivoting ramp part being proximate to and pivotally mounted on the main load support and the other extensible ramp part being mounted on the one pivoting ramp part, and the other extensible ramp part being slidably extendable in translational fashion relative to the one pivoting ramp part to increase the ramp surface and being slidably retractable to decrease the ramp surface.